The Free On-line Dictionary of Computing (30 December 2018):

Hitachi 6309
6309
HD6309

    (HD6309) Hitachi's version of the Motorola
   6809 microprocessor.  Compatible with the 6809, it added
   two new eight-bit registers that could be added to form a
   second 16-bit register, and all four eight-bit registers could
   form a 32-bit register.  It also featured division, and some
   32-bit arithmetic and was generally 30% faster in native mode.
   This information, surprisingly, was never published by
   Hitachi.

   Technical reference

(http://sandelman.ottawa.on.ca/People/Alan_DeKok/interests/6309.techref).

   (1997-03-21)